Conventional off-the-shelf virtual reality head-mounted displays support room-scale position tracking for a natural locomotion experience. However, physical spaces, usually small rooms inside end users' homes and video game arcades, are typically smaller than virtual spaces. A major challenge for virtual reality (VR) is embedding a large virtual space within a small, irregular, multi-user physical space while minimizing interruptions. The ideal solution would create the perception of infinite walking in the virtual space within a small, finite physical space. Treadmills or other physical devices can address the infinite walking problem but are undesirable for general applications because they are expensive, bulky, and can compromise the user's balance, while also preventing free user movements such as kneeling and jumping. Moreover, while using physical devices like these, acceleration and deceleration effects of natural walking are not felt, which can cause discomfort.
A straightforward solution to the problem of a limited physical space is to reset the virtual orientation whenever users hit the physical boundaries/obstacles of their room. Unfortunately, for large virtual environments, the viewpoints need to be reset often, which interrupts and degrades the quality of the user experience. An alternative to simply resetting the virtual orientation, is to redirect the user to avoid the physical boundaries/obstacles. Redirected walking techniques can enhance the immersion and visual-vestibular comfort of VR navigation, but are often limited by the size, shape, and content of the physical environments. The goal of redirection is to dynamically and imperceptibly manipulate a virtual environment to minimize how often a user hits boundaries of the room or an obstacle like furniture.
A first technique for redirecting a user increases rotation/transformation gains when the user rotates and/or moves his or her head, such that it causes the degree of head rotation visually perceived by the user to be slightly different from the actual rotation of their head. However, the head movement and the amount of redirection that may be achieved without negatively impacting the user's experience must be limited. A second technique for redirecting a user warps scene geometry so that the user's movements are guided through modified, re-rendered scenes. For example, the second technique may cause a straight hallway to appear curved to prevent the user from walking into a boundary or an obstacle. Warping causes distortion and is not suitable for open spaces within scenes. There is a need for addressing these issues and/or other issues associated with the prior art.